1. Field of the Invention
The invention relates to a smokable article comprising an aerosol generating zone which includes a combustion element and a carrier for an aerosol precursor which coaxially surrounds the combustion element, flow passages in the aerosol generating zone, a mouthpiece, and at least one outer sheath or wrapper.
2. Description of the Prior Art
Such a smokable article is disclosed in European Patent Publication No. 0 264 195 and comprises an aerosol generating zone consisting of a combustion element and a carrier for an aerosol precursor coaxially surrounding the combustion element as well as flow passages in the aerosol generating zone, a mouthpiece and possibly at least one sheath or wrapper for the aerosol generating zone and the mouthpiece.
In this known smokable article three longitudinal passages are provided in the aerosol generating zone and lie between the rod-shaped combustion element and the carrier for the aerosol precursor which in this embodiment is formed by a substrate of ceramic fibres. The advantage of this coaxial arrangement of inner combustion element and outer carrier for the aerosol precursor resides in the compact structure; a disadvantage is, however, the relatively poor heat transfer from the ignited combustion element to the aerosol precursor since the contact surface between the carrier and the combustion element is only relatively small. The air sucked in and flowing through the longitudinal passages between the combustion element and carrier is not sufficiently heated so that the necessary aroma amounts do not escape into the air from the aerosol precursor carrier. Moreover, there is no constrained guiding of the warm air through the aerosol precursor carrier so that the temperature necessary for the aerosol formation in the carrier is not reached.